Magnetic resonance imaging of myocardial perfusion in single-vessel coronary artery disease: implications for transmural assessment of myocardial perfusion.

Abstract

The purpose of the study was to investigate the potential of magnetic resonance imaging (MRI) to assess transmural differences in myocardial perfusion. Contrast-enhanced MRI was performed at rest and during hyperemia in a dog model and in 22 patients with single-vessel coronary artery disease. From MR signal intensity-versus-time curves, three perfusion parameters were derived: maximum myocardial contrast enhancement (MCE), slope, and inverse mean transit time (1/MTT). In dogs, MCE correlated well (r = 0.87, p < 0.00001) with microsphere-assessed myocardial blood flow. In the patients, the subendocardial MCE decreased during hyperemia (0.89 +/- 0.18 vs. 0.74 +/- 0.15, p < 0.003) and was lower in subendocardium than in subepicardium (0.74 +/- 0.15 vs. 0.84 +/- 0.21, p < 0.02). Parameters slope and 1/MTT paralleled MCE. Contrast-enhanced MRI reflects the transmural redistribution of myocardial perfusion during hyperemia. Perfusion abnormalities can be identified most distinctly in subendocardial myocardium.